The "civil problem" and local governments... The local courts are corrupt, especially when a property owner (like myself) can arbitrarily and falsely sue a rental tenant for damages which are really a failure to perform maintenance.
I have seen some homeowners "helped" by the courts, because they have connected friends or have bribed local officials screwing an honest working person to pay for remodels. The tax evasion is another question. Local contractors drawing up false bills for work never done to help their buddies in damage claims. They give the judge a cut buying the judgement award and all feast on the profit.
Slum lord economics. Kind of like Dianne Fiendstein. Get a suspect loan, buy a pile of junk, rent it out, sue the working tenants for money to remodel. This works especially well if you have a lot of Section 8 housing tenants and the government to carry the loan payments while you use your security deposits to file small claims against those who have jobs.
It is more difficult to do in a larger city unless you are one of the "in" crowd.
I have been aware of the Section 8 scam. I knew one case where the extended family owned the apartments, the single mother daughter rented it under Section 8, while working under the table and living with her working boyfriend husband, and then the family charging back repairs on non existing damage repairs to the feds.